Degradation of anthraquinone dye C.I. Reactive Blue 19 in aqueous solution by ozonation

This study investigated the degradation of anthraquinone reactive dye C.I. Reactive Blue 19 (RB-19) with initial concentration of 100 mg L⁻¹ in aqueous solution by ozone oxidation. The results of UV/VIS and FTIR spectra showed that the anthraquinone structures, nitrogen linkages and amino groups of RB-19 were destroyed under direct ozone reaction. The identification by LC–MS and GC–MS analyses indicated that some organic acids (e.g., phthalic acids) and 1,3-indanone could be the primary degradation products, respectively. The Microtox toxicity of the ozonated RB-19 solution initially increased but subsequently decreased when ozonation time increased. This detoxification accompanied biodegradability enhancement revealed by BOD/COD ratio increasing from 0.15 to 0.33 after 10 min of ozonation.